1. Field of the Invention
The invention relates to an installation path network for distribution areas having multiple subscriber stations arranged in a plurality of adjacent distribution areas.
2. Description of Related Art
Multiple subscriber stations serviced by a network of installation paths are known wherein the subscriber stations are interconnected to each other through subscriber lines within a distribution area emanating from a common distribution point for the distribution area. The entire system, which has a plurality of the distribution areas, is serviced from a center point with feeder lines connecting the distribution points for each of the distribution areas to the center point.
A conventional system is shown and discussed in "A Study on Node Placement for Video Distribution Services and Optical Subscriber Loops" in the Technical Research Report CS90-3, published by the Institute of Electronics, Information and Communication Engineers in Japan. In the disclosed distribution system, the nodes are placed at the center of each distribution area, as shown in FIG. 3 of the report. Such placement of the nodes is conventional, and the typical topology of an installation system requires that the distribution points or nodes for each distribution area be located in the center of the area.
The installation path or route topology having a distribution point or node in the center of each distribution area has advantages directed to the distribution of information throughout each distribution area. The performance of such a system, however, is not only judged by its effective distribution of information throughout the distribution area, but also by the cost for installing the route system in order to implement the distribution of information throughout the surface area.
Recently, the cost of the line or cable does not contribute to the greatest cost for installing the distribution network. The cost of the cable is being reduced as the result of mass-production, however, the cost of routing the cable or line throughout the distribution area is increasing due to labor costs. Each route that the cable or line follows requires an installation path for the route. Such installation paths are created by digging trenches or gutters for burying ducts or conduit through which the cable or line passes, erecting poles or stringing lines or cables between the poles for aerial route instruction, or just directly burying the line or cable. Recently, underground installation has been found to be more favorable in view of concerns about the environment and the aesthetics of aerial route installation.